The present invention relates to a method for forming a layer of soft magnetic alloy suitable to magnetic heads used for VTR and the like.
Hitherto, there has been known a method for forming a layer of soft magnetic nitride alloy by means of a reactive sputtering in Ar atmosphere containing nitrogen gas and a method for forming a layer of soft magnetic super structure nitride alloy comprising a nitride layer and a non-nitride layer by means of a reactive sputtering in Ar atmosphere periodically mixed with nitrogen gas (see Japanese Patent Koukai No. 210607/1987 and No. 254708/1988). There has been also known a method for forming a nitride alloy having a soft magnetic superstructure by means of applying a bias voltage on a substrate in an on/off manner with object of obtaining good and effective productivity of their layers (see Japanese Patent Koukai No. 15366/1989).
In these methods, however, there is relatively no problem where small a sputter target is used and the target is positioned opposite to a substrate, but there remains problems in that where a larger target is used in comparison to a distance between a substrate and a target, many oblique incident components of vapor deposited elements cause to magnetic anisotropy on the deposited layer, which does not become an isotropic soft magnetic one and does not show an isotropic high permeability.